Oil leaks may occur due to wear of the extension housing oil seal, or the vehicle speed sensor seal, and these are fairly easy to replace, and it is normally does not require that the transmission needs to be unbolted from the car. To perform the extension housing seal leak check, jack up the vehicle and securely support on jack stands: engage the parking brake and if equipped, turn off the air suspension system. A leaking extension housing seal will show transmission lubricant on the front of driveshaft and may drip down from rear of the transmission. Starting with the removal of driveshaft, tap the dust shoe if in place with a soft-face hammer so as not to distort it. Remove the extension housing seal without marring the splines of the trans output shaft. Replace the old extension housing seal with a new one with the assistance of a section of pipe or a deep socket, thereafter replacing the bushing should one be required. Lubricate the splines of the output shaft of the transmission and outside of the driveshaft sleeve yoke with light weight grease before installing the driveshaft making sure that you do not damage the lip of the new seal. After that, deflate the vehicle if you are using Air suspension system then switch it on. To access the vehicle speed sensor which is on the left side of the extension housing, you have to lift the vehicle and support it well and in case the vehicle is of air suspension type, then you should switch off the air suspension. A leaking sensor seal will mean that transmission lubricant will be seen dripping from the left side of the extension housing. Disconnect the electrical connector from the vehicle speed sensor then remove the bolt to hold the sensor and pull the sensor in a line with the opening. Remove the 0-ring and replace it, using lubrication on the new one so as to afford it protection during the process. Replace the sensor and grease the seal and the sensor with fresh engine oil and then lower the car and switch on the air suspension system if any.